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The origin of half of the elements heavier than iron -- the so-called r-process elements -- is a central unsolved mystery in astrophysics. These atoms include both precious metals (e.g. gold) as well as radioactive elements required for geophysical processes on the Earth (e.g. thorium) and even some which are necessary on Earth for advanced life (e.g. iodine). Recent observations with both light and gravitational waves have demonstrated that at least some of these elements are formed through the merger of two neutron stars comma but such a population struggles to reproduce the enrichment patterns seen in stars within the Milky Way as well apparent early enrichment in some dwarf galaxies. Instead comma recent work implies that the accretion disks formed in the stellar collapse that powers a long duration gamma-ray burst could in-fact be a dominant site. If this is true we should be able to observe r-process synthesis in the associated supernovae. The presence of lanthanides in r-process material creates strong opacity comma such that the signature of their synthesis should be a late time infrared component visible in the supernova light. Here we propose sensitive HST observations that will search for both spectroscopic and photometric evidence of the r-process comma providing the opportunity to test comma for the first time comma if collapsars are responsible for heavy element production.